Illuminating light selection device for a microscope

ABSTRACT

A microscope having a device for selectable illumination for observation of a specimen by ultraviolet light, DUV light, or by visible light, and which can keep ultraviolet light and visible light separate. The microscope includes a visible light illuminating system to illuminate a specimen with visible light, an ultraviolet light illuminating system to illuminate the specimen with ultraviolet light, a visible light observation system to observe the specimen illuminated by the visible light illuminating system, and an ultraviolet light observation system to observe the specimen by the ultraviolet light illuminating system. When a half mirror is arranged in the visible light illuminating system light path, a second illuminating light selection member screens the incidence of ultraviolet light into the visible light illuminating system and is moved into the visible light illuminating system light path, and when a fully reflecting mirror is arranged in the ultraviolet light illuminating system light path, a first illuminating light selection member screens the incidence of visible light into the ultraviolet light illuminating system moves into the ultraviolet light illuminating system light path.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a divisional of application Ser. No.09/382,460, filed Aug. 25, 1999, now allowed.

[0002] This application is based upon and claims priority of Japanesepatent application no. 10-246128 filed Aug. 31, 1998, and U.S. patentapplication Ser. No. 09/382,460, filed Aug. 25, 1999, the contents beingincorporated herein by reference.

BACKGROUND OF THE INVENTION

[0003] 1. Field of the Invention

[0004] The present invention relates to a microscope device, and, moreparticularly, the present invention relates to a microscope device whichcan selectively use ultraviolet light and visible light as illuminatinglight.

[0005] 2. Description of the Related Art

[0006] In recent years, semiconductor device structures have achievedincreased degrees of miniaturization. For example, in the case of a 16 Mdynamic RAM, the line width has become about 0.5 μm.

[0007] Microscopes having a high resolving power are necessary in orderto observe semiconductor devices having such a fine structure. The useof short wavelength light sources is one way in which to increaseresolving power of a microscope. Prior art microscopes have generallyused tungsten lamps, halogen lamps, or the like, visible light sources.However, these known light sources do not deliver ultraviolet light. Inparticular, with respect to extreme ultraviolet light (DUV) having awavelength of 300 nm or less, the amount of light necessary forobservation cannot be ensured.

[0008] Mercury lamps, and the like light sources, are used forillumination when ultraviolet light is required for observation.However, the image obtained using a mercury lamp is only a monochromeimage, and color information, which is one item necessary forinspection, cannot be obtained. Therefore, even with a microscope devicewith which observation using ultraviolet light is possible, it is alsonecessary to be able to perform observation using visible light.However, problems occur with a known illuminating system whichilluminates with both ultraviolet light (particularly DUV light) andvisible light.

[0009] A filter, dichroic mirror, or the like optical element, is usedto start to selectively isolate light of some wavelength. It is known touse a visible light illuminating system and an ultraviolet lightilluminating system in the same microscope, using this type of opticalsystem.

[0010] Because DUV light in particular is harmful to the human body, themicroscope device using a DUV light source must have a structure whichprevents incidence of the DUV light on the eye, even if by any chancethe DUV light should pass through the eyepiece lens of the microscope.However, because the known microscope device having a visible lightilluminating system and an ultraviolet light illuminating system in acommon observation system light path separates light using a dichroicmirror having predetermined wavelength selectivity, it is difficult tocompletely separate ultraviolet light and visible light. For example,when a laser or the like is used as an ultraviolet light source, thereis a risk that ultraviolet light passes through the dichroic mirror andleaks into the visible light observation system.

SUMMARY OF THE INVENTION

[0011] It is an object of the present invention to overcome the problemsof the prior art microscopes, and to provide a microscope which canselect one of ultraviolet light and visible light as illuminating light.

[0012] It is another object of the present invention to provide amicroscope device which can select one of ultraviolet light and visiblelight as illuminating light, and which reliably prevents ultravioletlight from being incident on the visible light observation system whenvisible light is selected.

[0013] Objects and advantages of the present invention are achieved inaccordance with embodiments of the present invention with a microscopedevice comprising a visible light illuminating system to illuminate aspecimen with visible light; an ultraviolet light illuminating system toilluminate the specimen with ultraviolet light; a visible lightobservation system to observe the specimen illuminated by the visiblelight illuminating system; an ultraviolet light observation system toobserve the specimen illuminated by the ultraviolet light illuminatingsystem; a first optical member to guide visible light to the specimen,which visible light is reflected from the specimen, and to guide lightreflected from the specimen to the visible light observation system; afirst illuminating light selection member to screen the ultravioletlight observation system from incidence of visible light; a secondoptical member to guide ultraviolet light to the specimen, whichultraviolet light is reflected from the specimen, and to guide lightreflected from the specimen to the ultraviolet light observation system;a second illuminating light selection member to screen the visible lightobservation system from incidence of ultraviolet light, wherein thefirst optical member and the first illuminating light selection memberare respectively selectively capable of arrangement in the visible lightilluminating system light path, and the second optical member and thesecond illuminating light selection member are respectively selectivelycapable of arrangement in the ultraviolet light illuminating systemlight path.

[0014] In accordance with embodiments of the present invention, thefirst illuminating light selection member is arranged in the visiblelight illuminating system light path when the first optical member isarranged in the visible light illuminating system light path, when thesecond illuminating light selection member is located in the ultravioletlight illuminating system light path, and when the second optical memberis arranged in the ultraviolet light illuminating system light path.

[0015] In accordance with embodiments of the present invention, when thefirst optical member is arranged in the visible light illuminatingsystem light path, the second illuminating light selection member movesto the ultraviolet light illuminating system light path. Further, whenthe second optical member is arranged in the ultraviolet lightilluminating system light path, the first illuminating light selectionmember moves to the visible light illuminating system light path.

[0016] In accordance with embodiments of the present invention, thesecond illuminating light selection member can be selected correspondingto the selected first optical member, and the first illuminating lightselection member can be selected corresponding to the selected secondoptical member.

[0017] In accordance with embodiments of the present invention, thefirst optical member and the second illuminating light selection memberare integrally formed, and the second optical member and the firstilluminating light selection member are integrally formed.

[0018] In accordance with embodiments of the present invention, it isnot necessary to respectively drive individually the first opticalmember and the second illuminating light selection member, and thesecond optical member and the first illuminating light selection member.Furthermore, the drive mechanism and guides, etc., can be small.Moreover, when electric motors are used to drive the members, the numberof drive motors can be small.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] These and other objects and advantages of the invention willbecome apparent and more readily appreciated from the followingdescription of the preferred embodiments, taken in conjunction with theaccompanying drawings of which:

[0020]FIG. 1 is a cross-sectional diagram of a microscope device in astate when a visible light illuminating system is selected to provide anilluminating light in accordance with a first embodiment of the presentinvention.

[0021]FIG. 2 is a cross-sectional diagram of a microscope device in astate when an ultraviolet light illuminating system is selected toprovide an illuminating light in accordance with a first embodiment ofthe present invention.

[0022]FIG. 3 is a perspective view of a second hollow block inaccordance with embodiments of the present invention.

[0023]FIG. 4 is a cross-sectional diagram of a microscope device in astate when a visible light illuminating system is selected to provide anilluminating light in accordance with a second embodiment of the presentinvention.

[0024]FIG. 5 is a cross-sectional diagram of a microscope device in astate when an ultraviolet light illuminating system is selected toprovide an illuminating light in accordance with a second embodiment ofthe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Reference will now be made in detail to the preferred embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings, wherein like reference numerals refer to likeelements throughout.

[0026] A first preferred embodiment of the present invention will bedescribed below with reference to FIGS. 1-3. FIGS. 1 and 2 arecross-sectional diagrams of a microscope device in accordance with thefirst embodiment of the present invention. More specifically, FIG. 1illustrates the microscope device in a state in which a visible lightilluminating system has been selected as the illuminating system, andFIG. 2 illustrates the microscope device in a state in which anultraviolet light illuminating system has been selected as theilluminating system. FIG. 3 is a perspective view of a second hollowblock arranged in an ultraviolet light illuminating system light path inaccordance with embodiments of the present invention.

[0027] As shown in FIGS. 1 and 2, the microscope device includes amicroscope body 10, a body tube 30, an electric motor revolvingnosepiece 40, a stage 50, and an ultraviolet light detector 60 to detectultraviolet light.

[0028] The microscope body 10 comprises a base 10A, a column 10B, and anarm 10D. A lamp housing 22A which houses a halogen lamp 22 is disposedon the back surface side of the arm 10D. Moreover, an ultraviolet imagedetection unit 10C is positioned in the upper portion of the arm 10D.The ultraviolet image detection unit 10C is detachable with respect tothe microscope body 10.

[0029] The body tube 30 is mounted on the top of the ultraviolet imagedetection unit 10C, and includes an eyepiece lens 31.

[0030] The ultraviolet light detector 60 is mounted on top of theultraviolet image detection unit 10C, and includes a CCD (not shown) forultraviolet light.

[0031] The electric motor revolving nosepiece 40 is mounted on a lowersurface of the arm 10D, and includes plural objective lenses 41, 42supported on the electric motor revolving nosepiece 40. The objectivelens 41 is for use with visible light and the objective lens 42 is foruse with ultraviolet light. A separate objective lens 41 for use withultraviolet is provided because it is difficult to make suitableaberration corrections in the same lens for both visible light andultraviolet light.

[0032] The stage 50 is disposed on the base 10A, and moves up and downalong the optical axis of the objective lenses 41, 42.

[0033] An ultraviolet light source, such as a mercury lamp 12, and anultraviolet light relay optical system comprising an ultraviolet filter13, relay lenses 14, 15, a shutter 16, a half mirror 17, and a secondhollow block 18 are arranged within the ultraviolet image detection unit10C.

[0034] When visible light observation is performed, the shutter 16 isdriven by a solenoid 16A such that the shutter 16 is inserted into theultraviolet light illuminating system light path so that ultravioletlight is not incident on the visible light illuminating system lightpath.

[0035] The second hollow block 18 includes a fully reflecting mirror 18A(FIGS. 2 and 3) and a light screening member 18B having a through hole18C (FIGS. 1 and 3). The second hollow block 18 can move in a directionat right angles (i.e., direction passing through the figure) withrespect to the light path of the mercury lamp 12. Accordingly, either ofthe fully reflecting mirror 18A or the light screening member 18B can bearranged with respect to the ultraviolet light illuminating system lightpath. When the light screening member 18B is arranged in the ultravioletlight illuminating system light path, a center axis of the through hole18C is positioned in the light path of the visible light observationsystem.

[0036] The second hollow block 18 is mounted on a fixed guide unit 19via a ball race (not shown) which rotatably supports a plurality ofballs 18 a, and is movable with respect to the fixed guide unit 19. Arack 18D (FIG. 3) is formed on an upper portion of the second hollowblock 18, and the rack 18D is engaged with a pinion 20A fixed to therotation shaft of a motor 20. The motor 20 is, for example, a DC motor.The motor 20 is fixed to the fixed guide unit 19.

[0037] A visible light source, such as a halogen lamp 22, and a visiblelight relay optical system comprising lenses 24, 25, and a first hollowblock 28 are arranged within the arm 10D.

[0038] The first hollow block 28 includes a half mirror 28A (FIG. 1) anda light screening member 28B (FIG. 2) having a through hole 28C (FIG.2). The first hollow block 28 can move in a direction at right angleswith respect to the light path of the halogen lamp 22 (i.e., a directionpassing through the figure). Accordingly, either of the half mirror 28Aor the light screening member 28B can be arranged with respect to thevisible light illuminating system light path.

[0039] When the light screening member 28B is arranged in the visiblelight illuminating system light path, the through hole 28C is positionedin the light path of the ultraviolet light observation system.

[0040] The first hollow block 28 is mounted on the fixed guide unit 29via a ball race mechanism (not shown) which rotatably supports aplurality of balls 28 a, and is capable of movement with respect to thefixed guide unit 29. A rack (not shown) is formed in the upper portionof the first hollow block 28. The rack is in gear engagement with apinion 26A fixed to the rotary shaft of a motor 26. The motor 26 is, forexample, a DC motor. The motor 26 is fixed to the fixed guide unit 29.

[0041] A dovetail formed on the lower surface of the ultraviolet imagedetection unit 10C is in engagement with a groove formed on the uppersurface of the arm 10D. Moreover, the internal space of the ultravioletimage detection unit 10C and the internal space of the arm 10D connectvia an aperture S. A light path is formed between the first hollow block28 and the second hollow block 18 by the aperture S.

[0042] When visible light is selected as the illuminating light, themotor 26 operates and the half mirror 28A is positioned in the visiblelight illuminating system light path, and furthermore, the motor 20operates and moves the light screening plate 18B into the ultravioletlight illuminating system light path. At this time, the through hole 18Cis arranged in the visible light observation system light path.

[0043] Illuminating light emitted from the halogen lamp 22 is reflectedby the half mirror 28A and is irradiated onto a predetermined region ofa specimen 51 via the objective lens 41 used for visible light. Theilluminating light optical system attains Koehler illumination withrespect to the specimen 51.

[0044] After passing through the half mirror 28A, reflected light fromthe specimen 51 passes through the aperture S and the through hole 18C,is imaged by an imaging lens 23 in the body tube 30, and is observed asvisible light by the eyepiece lens 31.

[0045] At this time, illuminating ultraviolet light from the mercurylamp 12 is screened off by the light screening member 18B and isscreened off by the shutter 16. Therefore, ultraviolet light is notirradiated onto the specimen 51 nor into the visible light illuminatingsystem (see FIG. 1).

[0046] As shown in FIG. 2, when ultraviolet light is selected as theilluminating light, the motor 20 operates and the fully reflectingmirror 18A is located in the ultraviolet light illuminating system lightpath, and the motor 26 operates and moves the light screening plate 28Binto the visible light illuminating system light path. At this time, thethrough hole 28C is arranged in the ultraviolet light observation systemlight path.

[0047] The light emitted from the mercury lamp 12 passes through theultraviolet filter 13 and becomes illuminating light, which isultraviolet light only, and does not contain visible light.

[0048] The illuminating light then passes through the relay lenses 14,15 for ultraviolet light use is transmitted through the half mirror 17,is reflected by the fully-reflecting mirror 18A, passes through theaperture S and through hole 28C to the objective lens 42 for use withultraviolet light and polarized, and is irradiated to a predeterminedregion on the specimen 51.

[0049] The illuminating light optical system is constructed to attainKoehler illumination with respect to the specimen 51.

[0050] Reflected light from the specimen 51 passes through the throughhole 28C and the aperture S, is reflected by the fully reflecting mirror18A, and is reflected by the half mirror 17 through to the detector 60for detecting ultraviolet light.

[0051] Light reflected by the half mirror 17 is imaged by the imaginglens 21 for use with ultraviolet light, and is received by the CCD forultraviolet light use in the ultraviolet light detector 60. Theultraviolet light received by the CCD for ultraviolet light use isconverted into electrical signals, made visible by a monitor (notshown), and is observed.

[0052] At this time, because the illuminating light from the halogenlamp 22 is screened off by the first illuminating light selection member28B, visible light is not irradiated to the specimen 51 nor to theultraviolet light observation system (see FIG. 2).

[0053] In accordance with the embodiment of the invention shown in FIGS.1-3, even when changing between observation with visible light andobservation with ultraviolet light, ultraviolet light and visible lightcan be reliably separated. As a result, even when using DUV light as thelight source, there is no risk of DUV light passing through the eyepiecelens and being incident on the eye of an observer.

[0054] Moreover, when ultraviolet light observation is performed,visible light can be prevented from entering the ultraviolet lightobservation system and giving rise to flare or ghosting.

[0055]FIGS. 4 and 5 are cross-sectional views a microscope device inaccordance with a second embodiment of the present invention. Elementsshown in FIGS. 4 and 5 which are the same as those shown in FIGS. 1-3,and described with respect to the first embodiment of the invention, arereferred to by the same reference symbols, and a detailed description ofthe like elements will not be repeated.

[0056]FIG. 4 shows a microscope in a state when visible light isselected as the illuminating light, and FIG. 5 shows a microscope in astate when ultraviolet light is selected as the illuminating light.

[0057] The embodiment of the invention shown in FIGS. 4 and 5 differsfrom the first embodiment of the invention in that the light screeningmember 18B is integrated with the upper portion of the half mirror 28A,and the fully-reflecting mirror 18A is integrated with the upper portionof the light screening member 28B, forming a block 108 having a two-stepconstruction, such that the block 108 is driven only by the motor 26 ofthe arm 10D.

[0058] In accordance with the embodiment of the invention shown in FIGS.4 and 5, results similar to those of the first embodiment are obtained.

[0059] Moreover, in accordance with the embodiment shown in FIGS. 4 and5, because individual driving of the first hollow block 28 and thesecond hollow block 18 is not necessary, there may be one each of amotor, rack and guide. Accordingly, the construction can be simplifiedand the cost reduced, resulting in an inexpensive device.

[0060] The present invention is not limited to the embodiment examplesdescribed above, and various modifications are possible. For example,the first hollow block 28 and the second hollow block 18 are driven bymotors in each of the above-described embodiments. However, the firsthollow block 28 and the second hollow block 28 may be made to be movedby hand.

[0061] Moreover, the half mirror 28A and the light screening member 28Bare formed integrally by the first hollow block 28. However, the halfmirror 28A and the light screening member 28B may be made separate.

[0062] Furthermore, the fully-reflecting mirror 18A and the lightscreening member 18B are formed integrally by the second hollow block18. However, the fully-reflecting mirror 18A and the light screeningmember 18B may be separate.

[0063] Moreover, in each of the above-described embodiments, theultraviolet light illuminating system is arranged above the visiblelight illuminating system. However, the visible light illuminatingsystem may be arranged above the ultraviolet light illuminating system.At this time, the detector 60 for detecting ultraviolet light is mountedon a side surface of the arm 10D.

[0064] Furthermore, in each of the above-described embodiments, amercury lamp was used as the ultraviolet light source. However, becauseit is difficult to provide a necessary and sufficient amount of lightfor observation, particularly in the case of DUV light, a laser whichirradiates ultraviolet light or DUV light may be used as the lightsource instead of the mercury lamp.

[0065] Moreover, the ultraviolet image detection unit 10C and arm 10Dhave been described as separable. However, if the visible light andultraviolet light are completely separated, each unit may be formed asan integral structure.

[0066] The microscope device described hereinabove in accordance withembodiments of the present invention reliably prevents entry ofultraviolet light into the visible light observation system light pathwhen visible light has been selected as the illuminating light.

[0067] The microscope device in accordance with embodiments of thepresent invention provides an easy operation of changing the type ofilluminating light, and prevents erroneous operation.

[0068] The microscope device in accordance with embodiments of thepresent invention provides a simplified structural design, and thestructural cost is reduced.

[0069] Although a few preferred embodiments of the present inventionhave been shown and described, it will be appreciated by those skilledin the art that changes may be made in these embodiments withoutdeparting from the principles and spirit of the invention, the scope ofwhich is defined in the claims and their equivalents.

What is claimed is:
 1. An illuminating light device to illuminate aspecimen, suitable for use in a microscope, comprising: a commonobservation system light path to direct illuminating light having one ofa first wavelength and a second wavelength to a specimen; and aprohibiting device to prohibit one of the illuminating light having thefirst wavelength and the illuminating light having the second wavelengthfrom incidence in the common observation system light path.
 2. Anilluminating light device as recited in claim 1 , wherein the lighthaving the first wavelength is visible light and the light having thesecond wavelength is ultraviolet light.
 3. An illuminating light deviceas recited in claim l, wherein the prohibiting device comprises: a firstilluminating light selection member, including a fully-reflecting mirrorto reflect the light having the second wavelength, and a light screeningmember to block the light having the second wavelength, wherein thefirst illuminating light selection member is movable between a positionin which the fully-reflecting mirror is in a light path of the lighthaving the second wavelength, and a position in which the lightscreening member is in a light path of the light having the secondwavelength.
 4. An illuminating light device as recited in claim 3 ,wherein the fully-reflecting mirror and the light screening member areformed integrally.
 5. An illuminating light device as recited in claim 3, wherein the prohibiting device further comprises: a secondilluminating light selection member, including a half mirror to reflectthe light having the first wavelength, and a second light screeningmember to block the light having the first wavelength, wherein thesecond illuminating light selection member is movable between a positionin which the half mirror is in a light path of the light having thefirst wavelength, and a position in which the second light screeningmember is in a light path of the light having the first wavelength. 6.An illuminating light selection device as recited in claim 5 , whereinthe half mirror and the second light screening member are integrallyformed.
 7. An illuminating light section device as recited in claim 5 ,further comprising: a selection device to select one of the light havingthe first wavelength as illuminating light and the light having thesecond wavelength as illuminating light, wherein the first illuminatinglight selection member is moved to a position in which the lightscreening member blocks the light having the second wavelength and thesecond illuminating light selection member is moved to a position inwhich the half mirror reflects light having the first wavelength inresponse to selecting the light having the first wavelength asilluminating light.
 8. An illuminating light section device as recitedin claim 5 , further comprising: a selection device to select one of thelight having the first wavelength as illuminating light and light havingthe second wavelength as illuminating light, wherein the secondilluminating light selection member is moved to a position in which thesecond light screening member blocks the light having the firstwavelength and the first illuminating light selection member is moved toa position in which the fully-reflecting mirror reflects light havingthe second wavelength in response to selecting the light having thesecond wavelength as illuminating light.
 9. An illuminating light deviceas recited in claim 5 , wherein the first and second illuminating lightselection members are integrally formed and move as a unit.
 10. Anilluminating light device as recited in claim 5 , wherein the first andsecond illuminating light selection members are separate members whichmove separately.
 11. An illuminating light device as recited in claim 9, wherein the light screening member is formed integrally with the halfmirror, and the second light screening member is formed integrally withthe fully-reflecting mirror.
 12. An illuminating light device as recitedin claim 1 , further comprising: a first illuminating system toilluminate the specimen with light having the first wavelength; a secondilluminating system to illuminate the specimen with light having thesecond wavelength; a first light observation system to observe thespecimen illuminated by the first light illuminating system; and asecond light observation system to observe the specimen illuminated bythe second light illuminating system, wherein the prohibiting deviceprohibits incidence of light having the first wavelength into the secondlight observation system.
 13. An illuminating device, suitable for usein a microscope, comprising: means for observing a specimen illuminatedby one of visible light and ultraviolet light; and means for stoppingincidence of ultraviolet light into the means for observing the specimenwhen the specimen is illuminated by the visible light.